Data retention using logical objects

ABSTRACT

Various embodiments are provided for facilitation of data retention using logical objects. Following an operation creating a redundant copy of the data performed on a scheduled interval, a logical object containing a number of managed file versions, represented by a number of member objects for a recovery point, is created. The logical object is assigned a policy of a data retention policy construct associated with the recovery point. The logical object is adapted for reassignment between policies of the data retention policy construct associated with various recovery points. During the reassignment, the plurality of member objects representing the plurality of managed file versions are logically retained instead of performing a data copy operation to associate the plurality of managed file versions with another recovery point.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to data storage systems, andmore particularly to apparatus, method and computer program productembodiments for facilitating data retention without requiring additionalbackup or data movement operations.

2. Description of the Related Art

Data backups are mechanisms well known in the industry that are used toallow users to restore their data due to failure of a component, humanerror, software corruption, or some other type of disaster. Data backupand archive procedures are implemented to solve two basic problems—dataprotection against hardware, software and human failure and dataretention for reference or audit purposes. The former type of protectionis typically short term, i.e., data is retained so that a file or systemcan be recovered to a point-in-time to some point within the recentpast, usually within some number of weeks. The latter is usually longterm, e.g., data has to be retained and remain accessible for severalyears. A data protection model might be retention of daily backups fortwo weeks (i.e., 12 copies of data representing each work day and oneweekend for two weeks), an additional set of backups made on theweekends to be retained for a period of two months (beyond the dailybackups), and finally a set of backups made at the end of each month tobe retained for long term archival for several years (beyond the weeklybackups).

SUMMARY OF THE INVENTION

Various embodiments are provided for facilitation of data retentionwithout requiring additional backup or data movement. In one embodiment,by way of example only, a method for archiving data by a processordevice applying a data retention policy construct is provided. Followingan operation creating a redundant copy of the data performed on ascheduled interval, a logical object containing a number of managed fileversions, represented by a number of member objects for a recoverypoint, is created. The logical object is assigned a policy of a dataretention policy construct associated with the recovery point. Thelogical object is adapted for reassignment between policies of the dataretention policy construct associated with various recovery points.During the reassignment, the plurality of member objects representingthe plurality of managed file versions are logically retained instead ofperforming a data copy operation to associate the plurality of managedfile versions with another recovery point. Related system and computerprogram product embodiments are also disclosed and provide additionaladvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict embodiments of the invention and are not therefore to beconsidered to be limiting of its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings, in which:

FIG. 1 is a block diagram of an exemplary computing environment in whichaspects of the present invention may be realized;

FIG. 2A is a block diagram of an exemplary storage manager including atleast two logical objects;

FIG. 2B is a block diagram of an additional exemplary storage managerincluding at least one logical object;

FIG. 3 is a flow chart diagram of an exemplary method for facilitatingdata retention using logical objects; and

FIG. 4 is a flow chart diagram of an exemplary method for facilitatingdata retention incorporating logical objects embodied a computer programproduct.

DETAILED DESCRIPTION OF THE DRAWINGS

Typically, the creation of archive data requires additional backupoperations and/or data movement. Several known backup mechanisms presentthis disadvantage, including grandfather-father-son (GFS) backups(requiring a full backup every week), progressive incremental backups(requiring maintenance of all incremental data up to six months), backupsets (requiring duplication at time of generation), and synthetic backupmechanisms (requiring retention of full and incremental backupinformation).

The illustrated embodiments present mechanisms for facilitating dataretention, such as rapidly creating archive data, without therequirement of additional backup operations and/or data movement. Thesemechanisms retain archive information but without incurring the cost ofcreating and/or maintaining additional copies of data. In one dataretention scenario, progressive incremental backup mechanisms achievefull backup redundancy by effectively taking only one full backup (thefirst backup operation), and forever after taking incremental backupsrelative to the last incremental backups. In this embodiment,progressive incremental backup mechanisms are exploited to reduce theamount of redundancy in daily backups and achieve long term recoverypoints without maintaining intermediate version storage, and withoutrequiring additional data copy operations.

The mechanisms of the present invention leverage a so-called “logicalobject” as a container to retain member objects representative ofmanaged file versions for a certain recovery point. These logicalobjects may be manipulated according to data retention policies assignedto them, rather than by resorting to data movement in and of itself.Accordingly, as certain data retention events take place, such as theoccurrence of data retention operations during a predefined interval,the logical objects may be reassigned to differing policies associatedwith differing recovery points. In some cases, the reassignmentincreases the length of time in which the managed file versionsassociated with member objects of a particular logical object areretained. In other cases, the reassignment expires the member objects,and thereby, the managed file versions, from the data repository. Inthis way, management of the various recovery points in a data retentionpolicy construct may be managed by management of the policies assignedto various logical objects without the additional requirement of datamovement or other data operations. This management will be illustratedin one exemplary embodiment, following, implementing a progressivebackup scheme according to regular backup intervals. The skilled artisanwill, however, realize that the mechanisms of the present invention maybe applied to a variety of data retention schemes using various policiesassociated with rotational frequencies.

Referring to FIG. 1, an exemplary computing environment is depicted inwhich the described embodiments may be realized. A server 2 is incommunication with multiple client computers 4 a, b, c over a network 6.The network 6 may comprise any network known in the art, such as theInternet, an Intranet, a Fibre Channel network, Storage Area Network(SAN), Local Area Network (LAN), etc. The multiple client computers 4 a,b, c maintain a file system 8 in a primary storage system 10, which maycomprise any storage system known in the art, such as a one or more harddisk drives, a Direct Access Storage Device (DASD), Just a Bunch ofDisks (JBOD), a Redundant Array of Independent Disks (RAID), tapelibrary, optical library, etc. The server 2 includes an operating system12 which may comprise any server-oriented operating system known in theart, such as IBM® z/OS®, AIX®, Microsoft® Windows®, etc. The server 2may comprise one or more server class computers. The clients 4 a, b, cmay comprise any computing device known in the art, such as a serverclass machine, a mainframe, desktop computer, laptop computer, hand heldcomputer, telephony device, etc.

The server 2 further includes a storage manager 20 that maintains abackup copy of the file system 24, including applications and/or data,in a backup storage 22. The storage manager may include a data retentionmanager/data retention program (described in further detail in FIGS. 2A,2B, following), which may include the functionality of any backupmanager known in the art, such as the IBM® Tivoli® Storage Managerprogram, in addition to the functionality of the describedimplementations. The backup storage 24 may comprise any suitablesecondary storage device for maintaining a backup copy of data, such asa tape storage system comprised of one or more tape drives and tapecartridges, an optical disk library, etc. The server 2 may communicatewith the backup storage 22 via any interface known in the art, such as abackplane interface in the server 2, parallel ports, serial ports, aSmall Computer System Interface (SCSI), a Fibre Channel arbitrated loop,a network, or any other interface known in the art.

The skilled artisan will appreciate that server 2 may contain variouscomponents in addition to the operating system 12 and storage manager 20which are not shown for purposes of convenience, such as a processor(s),memory devices, adapters, and the like. For example, the storage manager20 may operate, at least in part, as one or more processors executingthe operating system 12.

Turning to FIG. 2A, an exemplary block diagram of the functionality 50of storage manager 20 is depicted. Storage manager 20 includes dataretention manager 52 for implementing data retention mechanismsaccording to a policy construct. Data retention manager 52 includes anumber of policies 54. Each of the policies 54 of the data retentionmanager 52 is adapted to be applied according to a portion of the policyconstruct. For example, one policy 54 may be designed to retain databased on a daily rotation, while another policy may be designed toretain data based on a weekly or monthly rotation.

In the depicted embodiment, a logical object 56 is created as acontainer object for a number of member objects 64 representing managedfile versions at a certain recovery point. Similarly, logical object 58is created as a container object for a number of member objects 66representing managed file versions at an additional recovery point.Logical objects 56 and 58 function as container objects by logicallyholding the number of member objects 64. Member objects 64 are logicalmembers of the logical objects 56 and 58 to which the member objects 64are assigned. Member objects 64 are logical entities that represent, or“map to,” a wide variety of types of computer files, or blocks ofarbitrary information as of a certain recovery point, such as a specificdate. For example, one member object 64 may be a logical object thatrepresents a block of database information that is current as of Jan. 1,2009. Another member object 64 may be a logical object that representstext characters in a word processing document that is current as of Feb.1, 2009.

The skilled artisan will appreciate that a large amount of memberobjects 64 may exist for a certain recovery point. Each of the memberobjects 66 represent and/or are mapped to managed file versions. Inother words, the member objects 66 represent file versions that aremanaged by entities such as a backup manager. While the specificfunctionality of the backup manager is further described, following, thebackup manager may perform such actions relating to the management ofeach of the file versions. For example, an older version of a particularfile may be expired, or deleted from memory. A newer version of aparticular file may be retained.

It should be noted that member objects 64 and 66 may belong to more thanone container object. The functionality of logical objects will befurther described, following. The logical object 56 is assigned a policy60, and logical object 58 is assigned policy 62. In one embodiment,policy 60 may be a weekly rotation retention policy, while policy 62 maybe an additional weekly rotation retention policy.

In one embodiment, FIG. 2A represents a snapshot of the data retentionmanager 52 at a period of time. As will be further described, following,at a conclusion of a regularly scheduled backup interval in which aprogressive incremental backup operation is performed, the backupmanager 52 may create the logical object 56 for a particular recoverypoint. The data retention manager queries the inventory for all managedfile versions for the recovery point it is representing. Each of themanaged file versions is represented by a member object, which is thenassigned into the logical object 56. A number of member objects 64 areassigned into the logical object 56 in this way.

A policy 60 assigned by an administrator may be assigned to the logicalobject 56. In one embodiment, the policy 60 may be similar to the dailypolicy interval performed under a progressive backup scheme, but with anaccompanying duration (e.g., 14 days). Creation of the logical object 56and assignment of member objects 64 may proceed in an asynchronousmanner. In other words, the creation and assignment need not occurimmediately following the progressive incremental backup operation, butin one embodiment, preferably before the next scheduled backup is tooccur.

In similar fashion to the creation and assignment of logical object 56and member objects 64, the logical object 58 may be created followingthe progressive incremental backup operation of the next scheduledinterval (e.g., next day). Here again, the member objects 66representing all managed file versions for the next interval's recoverypoint are incorporated, and logical object 58 is assigned an additionaldaily-type policy 62 with an accompanying time duration (again, e.g.,two weeks).

Referring now to FIG. 2B, an additional functionality 72 of storagemanager 20 and backup manager 52 is depicted. At the conclusion of theduration of time of the policy 60 (FIG. 2A), and before the creation ofan additional logical object to be assigned an additional daily-typepolicy, the logical object 56 is reassigned/graduated to a policy 70representative of a lengthier retention (e.g., weekly instead of daily)and for a lengthier duration of time (e.g., eight weeks). This willensure that the logical object 56, and member objects 64 correspondingto managed file versions in the repository will be retained beyond theoriginal duration of the daily-type policy 60. The logical object 56 andmember objects are logically retained 64. In other words, no additionalbackup operation or data movement must take place.

In accordance with policy 62, once the logical object 56 is graduated toa new policy, the logical object 58 and corresponding member objects 66may then be expired from the repository. In this way, each of thelogical objects is logically reassigned or expired per operation ofpolicy, and are managed accordingly. At a point in the future, thelogical object 56 may be reassigned again to an additional policy (e.g.,monthly) with an accompanying lengthier duration of time. This scenariowill be further described, following.

Management of logical objects by reassignment/graduation and expirationby operation of policy is one aspect of the present invention andfollowing claimed subject matter. By management of the logical objectsthemselves, no additional data retention operations or data movementneed take place. The file versions represented by the member objects aremanaged through the management of the corresponding logical objects towhich they are assigned.

Turning to FIG. 3, a method 100 for rapidly creating archive data usingaspects of the present invention as previously described is illustrated.As one skilled in the art will appreciate, various steps in the method100 may be implemented in differing ways to suit a particularapplication. In addition, the described method 100 may be implemented byvarious means, such as hardware, software, firmware, or a combinationthereof operational on or otherwise associated with the storageenvironment. For example, the method 100 may be implemented, partiallyor wholly, as a computer program product including a computer-readablestorage medium having computer-readable program code portions storedtherein. The computer-readable storage medium may include disk drives,flash memory, digital versatile disks (DVDs), compact disks (CDs), andother types of storage mediums. While the method 100 is applicable tocomputer environments employing agents for data discovery and datamovement, and including a server for data storage and cataloging, theskilled artisan will appreciate that the method 100 may be generalizedto any network-based storage management mechanism.

Method 100 begins (step 102) with the creation of a new policy constructallowing an administrator/user to retain data on a certain schedule(step 104). For purposes of the illustrated embodiment, this schedulewill take the form of a daily, weekly, and monthly retention rotationschedule (DWM schedule). As a following step, a client (agent) performsan operation to retain data following a predetermined interval. In theillustrated embodiment, this operation involves executing a progressiveincremental back operation on a scheduled interval of one day (dailybackup) (step 106), although the skilled artisan will appreciate thatadditional data retention operations are contemplated.

At the conclusion of the progressive incremental backup, the backupmanager creates an object in the repository representing the recoverypoint (step 108). This object is a logical object. The backup managerqueries the inventory for all managed file versions for the recoverypoint it is representing, and all of the managed file versions,represented by member objects, are assigned into the logical object(step 109). For example, the server might determine that there are10,000 objects in the current repository that represent the desiredrecovery point. A single logical object is created and the 10,000 memberobjects are assigned as members of the logical object. Again, asdescribed previously, any member object may belong to a previous groupleader in a particular data retention scheme. The logical object isassigned a policy that allows retention similar to the “daily”provisions specified by the administrator, in this case, 14 days (step110). Again, note that logical object creation and member assignment canbe asynchronous in nature.

Following step 110, unless policy otherwise dictates, method 100 returnsto steps 106 to execute an additional progressive incremental backup onthe scheduled interval (e.g., an additional daily backup operation).This process continues for two weeks, as decision 111 queries whetherthe client has executed 14 daily backups or less. If so, the method 100returns to step 106 to execute the additional backup. After two weekshave elapsed, there are 14 logical objects representing the 14 dailybackups, which may be referred to as d0-d13 (daily backups oldest tonewest). The agent executes the 15th daily backup (d14) (step 112).

Before the creating of the logical object representing d14, the dataretention manager reassigns (graduates) the logical object d0 to thepolicy representing the “weekly” construct by the administrator, in thiscase, 8 weeks (step 118). Accordingly, logical object d0 is reassignedto the weekly policy as logical object w0. This will ensure that logicalobject d0 is maintained beyond the 14 days of its current policy (againas w0). After the 15 th daily backup (d14) and subsequent backups forthe week are created, logical object w0 is protected by the new policybut the logical objects d1-d6 and their corresponding member data (i.e.,member objects and associated data) can be expired from the inventory astheir policy dictates (step 120). Method 100 then returns to step 106 toperform additional progressive incremental backup operations on thescheduled interval, and additional logical objects are created andmember objects assigned accordingly.

After three weeks have elapsed, logical objects w0 and d7-d20 aremaintained by the server. When the client executes the 22^(nd) dailybackup, and according to decision 114, a similar scenario is carried outas before, where logical object d7 is graduated to the weekly policy(step 122) to become logical object w1 and logical objects d8-d13 areexpired off as the new backups (d21-d27) are created (step 124). Method100 returns to step 106 and continues as before.

After one month has elapsed, the server maintains logical objects w0,w1, and d14-d27. The server graduates w0 to the policy representing the“monthly” construct, in this case 6 months (step 126) as logical objectm0, and expires relevant logical objects per policy (e.g., logicalobjects w1, and d14-d27) (step 128). Method 100 then returns again tostep 106 and continues as before.

While not shown, the skilled artisan will appreciate that at some pointin the future, various logical objects may continue to be reassigned asother logical objects are expired per operation of policy. This processcontinues as before, as new logical objects are reassigned, and othersare expired from the repository. To accurately maintain the DWMschedule, the server may maintain graduation heuristics that dictatewhich daily versions graduate to weekly versions, and which weeklyversions graduate to monthly versions. These graduation heuristics willvary according to a particular implementation of policy. The skilledartisan will appreciate that while the illustrated embodiment representsan example of a daily/weekly/monthly data retention model, the timeintervals specified may be arbitrary and may map to a variety of othermodels of rotation. Each reassignment decision, and accordingly,management of various recovery points associated with particular logicalobjects, may be directed according to the operation of the policies towhich the logical objects are assigned.

FIG. 4, following, is a flow chart diagram of a method 150 depictingexemplary computer program product-implemented steps for carrying outvarious aspects of the present invention. Method 150 begins (step 152)following an operation creating a redundant copy of the data performedon a scheduled interval. A first executable portion creates logicalobject containing a plurality of managed file versions represented by aplurality of member objects for a first recovery point (step 154). Asecond executable portion then assigns the logical object a first policyof the data retention policy construct associated with the firstrecovery point (step 156). The logical object is adapted forreassignment from the first policy to a second policy of the dataretention policy construct associated with a second recovery point.During the reassignment the plurality of member objects representing theplurality of managed file versions are logically retained instead ofperforming a data copy operation to associate the plurality of managedfile versions with the second recovery point. Here again, logicalretention (or expiration) of the plurality of member objects isperformed rather than data movement of additional data retentionoperations on the managed file versions represented by the memberobjects, according to operation of policy, to manage the variousrecovery points.

By implementation of various aspects shown in the illustratedembodiments, management of logical objects provides for creation ofarchive data without encumbering additional resources such as requiringadditional data movement or data retention operations such as backupoperations. While one or more embodiments of the present invention havebeen illustrated in detail, the skilled artisan will appreciate thatmodifications and adaptations to those embodiments may be made withoutdeparting from the scope of the present invention as set forth in thefollowing claims.

1. A method for retaining data by a processor device applying a dataretention policy construct in a data storage system, comprising:following an operation creating a redundant copy of the data performedon a scheduled interval, creating a logical object containing aplurality of managed file versions represented by first a plurality ofmember objects each generated on a first periodic basis for a firstpredetermined amount of time; assigning the logical object a first dataretention policy, wherein the first plurality of member objects areadapted for reassignment from the first data retention policy to asecond data retention policy to generate a second plurality of memberobjects on a second periodic basis for a second predetermined amount oftime at an incremental expiration of the first periodic basis for thefirst predetermined amount of time; and reassigning the logical objectfrom the first data retention policy to the second data retentionpolicy, wherein each of the first plurality of member objects arereassigned from the first data retention policy to the second dataretention policy at each incremental expiration of the firstpredetermined amount of time for each respective member object in thefirst plurality of member objects, wherein during said reassignment ofthe logical object, the second plurality of member objects are logicallyretained in the logical object instead of performing a data copyoperation on the second plurality of member objects.
 2. The method ofclaim 1, wherein the logical object is further adapted for additionalreassignment from the second data retention policy to a third dataretention policy to generate a third plurality of member objects on athird periodic basis for a third predetermined amount of time at anincremental expiration of the second periodic basis for the secondpredetermined amount of time.
 3. The method of claim 1, wherein thefirst data retention policy establishes a first predetermined time forwhich the logical object retains the plurality of member objects, andthe second data retention policy establishes a second predetermined timefor which the logical object retains the plurality of member objects,further wherein the second predetermined time is longer than the firstpredetermined time, and the reassignment from the first data retentionpolicy to the second data retention policy occurs following theincremental expiration of the first predetermined time.
 4. The method ofclaim 1, further including managing the first predetermined amount oftime, the second predetermined amount of time and additionalpredetermined amounts of time by managing assignments of the logicalobject between a plurality of data retention policies associated withthe predetermined amount of time, the second predetermined amount oftime, and the additional predetermined amounts of time.
 5. The method ofclaim 1, wherein the operation creating the redundant copy of the dataincludes a progressive incremental backup operation performed on ascheduled interval.
 6. The method of claim 1, wherein creating thelogical object containing the plurality of managed file versionsrepresented by the plurality of member objects for the firstpredetermined amount of time is performed asynchronously with theoperation creating the redundant copy of the data.
 7. A system forretaining data, comprising: a processor device applying a data retentionpolicy construct as part of a storage management scheme in a datastorage system, wherein the processor device is adapted for: followingan operation creating a redundant copy of the data performed on ascheduled interval, creating a logical object containing a plurality ofmanaged file versions represented by a first plurality of member objectseach generated on a first periodic basis for a first predeterminedamount of time; assigning the logical object a first data retentionpolicy, wherein the first plurality of member objects are adapted forreassignment from the first data retention policy to a second dataretention policy to generate a second plurality of member objects on asecond periodic basis for a second predetermined amount of time at anincremental expiration of the first periodic basis for the firstpredetermined amount of time; and reassigning the logical object fromthe first data retention policy to the second data retention policy,wherein each of the first plurality of member objects are reassignedfrom the first data retention policy to the second data retention policyat each incremental expiration of the first predetermined amount of timefor each respective member object in the first plurality of memberobjects, wherein during said reassignment of the logical object, thesecond plurality of member object are logically retained in the logicalobject instead of performing a data copy operation on the secondplurality of member objects.
 8. The system of claim 7, wherein thelogical object is further adapted for additional reassignment from thesecond data retention policy to a third data retention policy togenerate a third plurality of member objects on a third periodic basisfor a third predetermined amount of time at an incremental expiration ofthe second periodic basis for the second predetermined amount of time.9. The system of claim 7, wherein the first data retention policyestablishes a first predetermined time for which the logical objectretains the plurality of member objects, and the second data retentionpolicy establishes a second predetermined time for which the logicalobject retains the plurality of member objects, further wherein thesecond predetermined time is longer than the first predetermined time,and the reassignment from the first data retention policy to the seconddata retention policy occurs following the incremental expiration of thefirst predetermined time.
 10. The system of claim 7, wherein theprocessor device is further adapted for managing the first predeterminedamount of time, the second predetermined amount of time and additionalpredetermined amounts of time by managing assignments of the logicalobject between a plurality of data retention policies associated withthe first predetermined amount of time, the second predetermined amountof time, and the additional predetermined amounts of time.
 11. Thesystem of claim 7, wherein the operation creating the redundant copy ofthe data includes a progressive incremental backup operation performedon a scheduled interval.
 12. The system of claim 7, wherein theprocessor device is further adapted for, during the creating the logicalobject containing the plurality of managed file versions represented bythe plurality of member objects for the first predetermined amount oftime, performed the creating the logical object asynchronously with theoperation creating the redundant copy of the data.
 13. The system ofclaim 9, wherein the first predetermined amount of time is approximately14 days in length, and the second predetermined amount of time isapproximately eight weeks in length.
 14. A computer program product forarchiving data by a processor device applying a data retention policyconstruct, the computer program product comprising a computer-readablestorage medium having computer-readable program code portions storedtherein, the computer-readable program code portions comprising: a firstexecutable portion for, following an operation creating a redundant copyof the data performed on a scheduled interval, creating a logical objectcontaining a plurality of managed file versions represented by a firstplurality of member objects each generated on a first periodic basis fora first predetermined amount of time; a second executable portion forassigning the logical object a first data retention policy, wherein thefirst plurality of member objects are adapted for reassignment from thefirst data retention policy to a second data retention policy togenerate a second plurality of member objects on a second periodic basisfor a second predetermined amount of time at an incremental expirationof the first periodic basis for the first predetermined amount of time;and a third executable portion for reassigning the logical object fromthe first data retention policy to the second data retention policy,wherein each of the first plurality of member objects are reassignedfrom the first data retention policy to the second data retention policyat each incremental expiration of the first predetermined amount of timefor each respective member object in the first plurality of memberobjects, wherein during said reassignment of the logical object, thesecond plurality of member objects are logically retained in the logicalobject instead of performing a data copy operation on the secondplurality of member objects.
 15. The computer program product of claim14, wherein the logical object is further adapted for additionalreassignment from the second data retention policy to a third dataretention policy to generate a third plurality of member objects on athird periodic basis for a third predetermined amount of time at anincremental expiration of the second periodic basis for the secondpredetermined amount of time.
 16. The computer program product of claim14, wherein the first data retention policy establishes a firstpredetermined time for which the logical object retains the plurality ofmember objects, and the second data retention policy establishes asecond predetermined time for which the logical object retains theplurality of member objects, further wherein the second predeterminedtime is longer than the first predetermined time, and the reassignmentfrom the first data retention policy to the second data retention policyoccurs following the incremental expiration of the first predeterminedtime.
 17. The computer program product of claim 14, further including afourth executable portion for managing the first predetermined amount oftime, the second predetermined amount of time and additionalpredetermined amounts of time by managing assignments of the logicalobject between a plurality of data retention policies associated withthe first predetermined amount of time, the second predetermined amountof time, and the additional predetermined amounts of time.
 18. Thecomputer program product of claim 14, wherein the operation creating theredundant copy of the data includes a progressive incremental backupoperation performed on a scheduled interval.
 19. The computer programproduct of claim 14, wherein creating the logical object containing theplurality of managed file versions represented by the plurality ofmember objects for the first predetermined amount of time is performedasynchronously with the operation creating the redundant copy of thedata.